From: Jessica Zhang Date: Sun, 24 May 2026 10:33:31 +0000 (+0300) Subject: drm/msm/dp: Read DPCD and sink count in bridge detect() X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0f2293dfb5fe525cd79c2ff2a59e4bec387baba5;p=thirdparty%2Fkernel%2Fstable.git drm/msm/dp: Read DPCD and sink count in bridge detect() Instead of relying on the link_ready flag to specify if DP is connected, read the DPCD bits and get the sink count to accurately detect if DP is connected. Signed-off-by: Jessica Zhang Tested-by: Val Packett # x1e80100-dell-latitude-7455 Tested-by: Yongxing Mou # Hamoa IOT EVK, QCS8300 Ride Signed-off-by: Dmitry Baryshkov Reviewed-by: Konrad Dybcio Patchwork: https://patchwork.freedesktop.org/patch/727603/ Link: https://lore.kernel.org/r/20260524-hpd-refactor-v6-3-cf3ab488dd7b@oss.qualcomm.com --- diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c index cf2415635c42..77f1ae5d7210 100644 --- a/drivers/gpu/drm/msm/dp/dp_display.c +++ b/drivers/gpu/drm/msm/dp/dp_display.c @@ -1152,6 +1152,69 @@ static int msm_dp_hpd_event_thread_start(struct msm_dp_display_private *msm_dp_p return 0; } +/** + * msm_dp_bridge_detect - callback to determine if connector is connected + * + * @bridge: Pointer to drm bridge structure + * @connector: Pointer to drm connector structure + * + * Returns: where there is a display connected to the DPTX (returning + * disconnected for branch devices without DP Sinks being connected). + */ +enum drm_connector_status msm_dp_bridge_detect(struct drm_bridge *bridge, + struct drm_connector *connector) +{ + struct msm_dp_bridge *msm_dp_bridge = to_dp_bridge(bridge); + struct msm_dp *dp = msm_dp_bridge->msm_dp_display; + int status = connector_status_disconnected; + struct msm_dp_display_private *priv; + u8 dpcd[DP_RECEIVER_CAP_SIZE]; + struct drm_dp_desc desc; + int ret; + + dp = to_dp_bridge(bridge)->msm_dp_display; + + priv = container_of(dp, struct msm_dp_display_private, msm_dp_display); + + if (!dp->link_ready) + return status; + + msm_dp_aux_enable_xfers(priv->aux, true); + + ret = pm_runtime_resume_and_get(&dp->pdev->dev); + if (ret) { + DRM_ERROR("failed to pm_runtime_resume\n"); + msm_dp_aux_enable_xfers(priv->aux, false); + return status; + } + + ret = msm_dp_aux_is_link_connected(priv->aux); + if (dp->internal_hpd && !ret) + goto end; + + ret = drm_dp_read_dpcd_caps(priv->aux, dpcd); + if (ret) + goto end; + + ret = drm_dp_read_desc(priv->aux, &desc, drm_dp_is_branch(dpcd)); + if (ret) + goto end; + + status = connector_status_connected; + if (drm_dp_read_sink_count_cap(connector, dpcd, &desc)) { + int sink_count = drm_dp_read_sink_count(priv->aux); + + drm_dbg_dp(dp->drm_dev, "sink_count = %d\n", sink_count); + + if (sink_count <= 0) + status = connector_status_disconnected; + } + +end: + pm_runtime_put_sync(&dp->pdev->dev); + return status; +} + static irqreturn_t msm_dp_display_irq_handler(int irq, void *dev_id) { struct msm_dp_display_private *dp = dev_id; diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c index fd6443d2b6ce..e4622c85fb66 100644 --- a/drivers/gpu/drm/msm/dp/dp_drm.c +++ b/drivers/gpu/drm/msm/dp/dp_drm.c @@ -15,26 +15,6 @@ #include "dp_audio.h" #include "dp_drm.h" -/** - * msm_dp_bridge_detect - callback to determine if connector is connected - * @bridge: Pointer to drm bridge structure - * @connector: Pointer to drm connector structure - * Returns: Bridge's 'is connected' status - */ -static enum drm_connector_status -msm_dp_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector) -{ - struct msm_dp *dp; - - dp = to_dp_bridge(bridge)->msm_dp_display; - - drm_dbg_dp(dp->drm_dev, "link_ready = %s\n", - str_true_false(dp->link_ready)); - - return (dp->link_ready) ? connector_status_connected : - connector_status_disconnected; -} - static int msm_dp_bridge_atomic_check(struct drm_bridge *bridge, struct drm_bridge_state *bridge_state, struct drm_crtc_state *crtc_state, diff --git a/drivers/gpu/drm/msm/dp/dp_drm.h b/drivers/gpu/drm/msm/dp/dp_drm.h index 9eb3431dd93a..6c0426803d78 100644 --- a/drivers/gpu/drm/msm/dp/dp_drm.h +++ b/drivers/gpu/drm/msm/dp/dp_drm.h @@ -25,6 +25,8 @@ int msm_dp_bridge_init(struct msm_dp *msm_dp_display, struct drm_device *dev, struct drm_encoder *encoder, bool yuv_supported); +enum drm_connector_status msm_dp_bridge_detect(struct drm_bridge *bridge, + struct drm_connector *connector); void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge, struct drm_atomic_state *state); void msm_dp_bridge_atomic_disable(struct drm_bridge *drm_bridge,